SUCCESS STORY
With "Peak Shaving" to the Energy Turnaround
MANN group of companies optimizes power consumption with energy meter modules from Helmholz. Green energy from regional sources is not just a successful business model for the MANN group of companies, but a conviction.
Whether wind power, biomass or wood pellets: For more than 25 years, the MANN group of companies based in the Westerwald town of Langenbach has stood for a sustainable, green energy supply from local sources. The vision of a regionally driven energy turnaround is of course also being implemented by those responsible in-house, as the company itself is a major energy consumer.
The production of wood pellets by the subsidiary Westerwälder Holzpellets offers a significant starting point for optimizing electricity consumption. The so-called chipper alone, for example, in which whole tree trunks are crushed by machine, requires up to 320 kW of electricity. But the subsequent pressing or shredding of wood waste for the company's own biomass power plant also draws a lot of power. Exactly how much has recently been revealed by the systematic recording and transparent evaluation of the electrical energy flows on the plant site.
Peak Shaving" project
Continuous documentation of instantaneous consumption makes it possible to forecast short- and medium-term power requirements and thus to perform peak shaving. Impending load peaks can thus be detected in good time and avoided by switching off individual consumers for short periods or by intelligently scheduling shiftable loads. The underlying database is also clearly visualized and displayed in a "current tachometer" with three warning levels.
"Green" indicates low current consumption, "yellow" indicates rising consumption, and "red" indicates an imminent load peak. The following example shows what this means in practical operation: The chipper of the pellet mill is loaded with logs via an excavator. During this process, the excavator operator constantly monitors the power consumption via a tablet. If it approaches the "red" zone, he can interrupt the feed of new logs and thus reduce the power requirement for a short time. This break can then be used to fetch new logs from the log yard.
Another example of consumers that can be switched off without any problems are the E-filling stations on the company premises, where employees and external customers can charge their electric vehicles. If the charging process is interrupted for a few minutes, they do not notice anything. Nevertheless, short-term load peaks can be effectively avoided without much effort.
„Super support, especially during the test phase“ and „the Helmholz devices are really very easy to use“
Florian Höfer, responsible for electrical engineering and plant programming at Westerwälder Holzpellets
Technical implementation
Florian Höfer, responsible for electrical engineering and plant programming at Westerwälder Holzpellets, implemented this solution technically. To do this, he first created an intelligent network structure as a prerequisite. The company-wide area network includes both the individual consumers and full feeders such as biomass power plant (BMKW), combined heat and power plant (CHP) and photovoltaic systems on the premises. This infrastructure enables systematic condition monitoring of all relevant plants.
To this end, in the first step, key parameters relating to current and voltage, such as active/apparent power, etc., are recorded in real time at a total of 14 measuring points. This task is performed by the decentralized and fieldbus-spanning TB20 I/O system from Helmholz. One I/O module is used for each measuring point. The compact devices are equipped with an "Energy Meter" function module. Via a Modbus/TCP interface, the recorded data is then transferred to a monitoring software for further processing, where - in a second step - it is analyzed and visualized.
Florian Höfer configured the basic version of the software according to his individual requirements and has since been constantly developing it further. In addition, a PROFINET/ Modbus coupler - also supplied by Helmholz - integrates the pellet plant into the Modbus. Process data from the corresponding PROFINET machine network can thus be mapped and used directly in the monitoring software, for example to monitor efficiency and plant operation.
All TB20 modules are quickly and reliably plugged onto the DIN rail while the rest of the system continues to run. The hot-swappable electronic modules minimize downtime.
Decision for Helmholz
The decision in favor of the TB20 I/O system was made after extensive tests with Modbus/TCP-capable measuring devices from different manufacturers. From Florian Höfer's point of view, one argument in particular spoke in favor of Helmholz as the supplier in this comparison: "The Helmholz devices are really very easy to operate!" And the automation professional also gives an example right away: "The connectors on top can be easily removed and put back on again.
So if a card should ever be defective - due to an operating error, for example - it can be replaced easily and quickly without disconnecting the cables." Höfer also cites the "super support, especially during the test phase" as a second argument. The Helmholz experts, he reports, "solved problems that were unsolvable for me in five minutes." And last but not least, the price/performance ratio of the TB20 components also convinced him.
These Helmholz Products are in use at Mann Group
Results and outlook
The peak shaving measures that have now been implemented have indeed significantly reduced the load peaks: While the maximum value was previously 1,780 kW, it was recently only 1,507 kW at peak. This is also noticeable in terms of costs: The so-called capacity charge, which companies pay in addition to consumption costs, depends exclusively on the maximum capacity during a billing period - regardless of how long it is called up.
In return, this means that the capacity charge is reduced considerably due to lower peak loads. For the companies of the MANN Group, this saving amounts to a five-digit sum per year. At the same time, practical operation has shown that the actual shutdown times are shorter than expected: For example, the outages - viewed across all consumers - affect less than one percent of the operating hours. For the consumers most affected, the electricity charging stations, the figure is three percent.
"We have thus proven on a small scale that the equalization of power peaks through the intelligent management of shiftable loads works," Florian Höfer sums up. "And with this, we also see ourselves as pioneers for implementing 'peak shaving' on a larger scale, because this is really an important thing for the future of the energy transition."
Until that time comes, however, company boss Markus Mann and his people from the MANN group of companies are first pushing ahead with a few more projects for the future: for example, a 1.4 MW battery storage system made from 114 recycled car batteries is currently being built on the plant site to buffer regenerative power sources. And by integrating new wind turbines, the company will also produce electricity for feeding into the public grid for the first time from mid-2021. What will come next? - In any case, the Westerwalders are not lacking in innovative ideas.
